Answer:
b. 2.9!
Step-by-step explanation:
There are is a mistake in the question.
Suppose the group consist of 10 kids and 2 adults, the number of ways in which they can form the line is:
= 2! 10!
= 2× 1× 10!
= 2.10!
But since that is not in the given option.
Let assume that the group consists of 9 kids and 2 adults, the number of ways in which they can form the line is:
No of ways the kids can be permutated = 9 ways
No of ways the adult can be permutated = two ways.
Thus; the number of ways in which they can form the line = 2! 9!
= 2 × 1× 9!
= 2.9!